Another Aftermaket Brake Light Problem

[pablooo]

After exhausting all motobrick topics I could find on this subject, and there are a lot of them, I think it's time to finally post up my problem.


I have just installed a new Aftermarket Dual Intensity LED brake/running/turn signal Strip. ( https://www.radiantz.com/product-p/6126-61.htm ) it is like the one linked except non -sequential. I installed it and the turn signals work perfectly. The problem I'm having is that when I have the key in the full on position and the killswitch straight up, it's as if the brake light is on and just stays that way. It's at the brightest setting and won't change if I press the rear or front brakes. I found out that if I keep the key in the full on position but move the killswitch to either side, the LED will go into the tail light brightness which is lower than if I were to hit the brakes. I went through different forum posts and maybe thought it'd be the front or rear brake light switches that might be stuck but after unplugging one at a time and trying them out one at a time and together nothing changed. I traced each of the wires to see if anything was shorting or anything was wired in the wrong way but nope. I looked at the BMU but everything looked good and no fuse was out as the front parking lamp was still good.


I decided to try another LED Strip that I have that is also a dual intensity brake strip except it's just a brake light/tail light (no turn signals) and the same problem came up except this time when I tried hitting the front or rear brake, the whole light would just turn off completely. Once I let go of the brakes, it comes back to full brightness. No change in intensity at all. This also showed me that it can't be the brake switches as the LED Would've just stayed off completely until unplugging the faulty switches but it isn't either. I've gone through this forums posts as well as other forums and can't find anything. I haven't changed any sort of wiring having to do with the brake and rear lights at all. I made sure my wiring was correct and I didn't install the wiring the wrong way but I'll post how I did that on here.


BIKE -> LED STRIP


GROUND (brown)  -> Ground (Black)


TAIL LIGHT (Black/Grey) -> Running (low Intensity) (Orange)


REAR RIGHT TURN (Blue/Black) -> Right Turn (Brown)


BRAKE LIGHT (Yellow/Grey) -> Brake (high Intensity)(Red)


REAR LEFT TURN (Blue/Red) -> Left Turn (Purple)






Any help would be appreciated.

[Laitch]

I made sure my wiring was correct and I didn't install the wiring the wrong way . . ..
Any help would be appreciated.

If it were my bike, I'd review how I wired the grounds and change something there. First though, I'd need to admit I might have made an error. :giggles

[Martin]

I believe there is a modification that involves cutting one of the tracks in the BMU which will allow you to run LED's. Try searching for BMU modifications or LED modifications.
Regards Martin.

[pablooo]

If it were my bike, I'd review how I wired the grounds and change something there. First though, I'd need to admit I might have made an error. :giggles

Who? Me?! Be wrong?! Never!...but in all seriousness, at least in my mind when wiring it up I didn't think I could mess it up since it just went straight to the other 5 wires on the LED strip  but here I am. Maybe it was too good to be true to be so easy. I can go a bit blank sometimes especially when working with electrical stuff.


Any idea on how to change the way the grounds are wired? I checked up on the grounds themselves on and where they're anchored on the frame and seemed to be clean and good to go. the slightly thicker gauge wire coming from the bike going to the single ground wire needed on the LED strips wouldn't make a difference would it? From what I was told,  as long as the source ground wire is the bigger wire then it will be fine? (Again though, this came from another poster on some other forum so I'm all here for ideas and thoughts) 

[pablooo]

I believe there is a modification that involves cutting one of the tracks in the BMU which will allow you to run LED's. Try searching for BMU modifications or LED modifications.
Regards Martin.

I did see those forum posts on here but for some reason I only thought of them being for the hyperglashing of LED's but after another read through makes it seem that it might be able to solve my problem. I will be doing the cut as instructed here ( http://www.motobrick.com/index.php/topic,659.0.html )  and see if that solves my problem and if not then I will just go ahead and use this forum post ( http://www.motobrick.com/index.php/topic,331.0.html ) as an instructional to bypass the BMU altogether and hopefully that will solve my problem.

[rbm]

The flasher module and the brake monitoring unit are two separate systems on the bike and not related. 


LED signal lights hyperflash with the standard BMW flasher module. There are two different modifications that can be performed on the flasher module to solve this problem -- one involves cutting a PCB trace and the other involves manufacturing a LED compatible module (your link). 


There is another totally different modification to the BMU that involves gutting the internals and jumping the pins on the connector that solves brake light problems.


You will have to do both modifications.

[pablooo]

There is another totally different modification to the BMU that involves gutting the internals and jumping the pins on the connector that solves brake light problems.


You will have to do both modifications.

Do you happen to remember the title or maybe the link of the post to gutting the BMU as you said? The hyperflashing I can deal with (although I will also be doing that modification as well) but the brake light is the one I'm wanting to do today and need to fix asap. It's not this one is it? http://www.motobrick.com/index.php/topic,331.0.html

[rbm]

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/bmu/bmu.htm

[pablooo]

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/bmu/bmu.htm

Yup. Looks like the same thing just posted on this forum it seems. To be clear, when it says to short the specified wires together after removing the BMU, does it just mean connecting them together basically? My electronics dictionary isn't very good and don't want to mess anything more up.

[rbm]

Yes, that's what it means.  The advantage to gutting the BMU is that you can remove your shorting jumpers later and restore OEM functionality.  Alternatively, you can[/size] have a fully functional BMU that you can sell if you you plan never to restore the OEM functionality.  That's probably a better idea given that parts for K-bike are getting scarcer all the time.

[Chri5]

i new here and have zero experience with K bike electrics (yet) but heres my two pence from past work with LEDs, BMW cars and my electric motobike (my pride and joy) my first question is there a resistive load module with the light? usualy a block for the bike loom inputs to go into the the wired on towards the light (or an actual inline (some times ceramic) resistors on the wires) form i BMW 5 series i wired up with LEDs the BMU really doesnt like them the lights i installed had SMD(surfacemount) resistors which didnt works so i had to put 10w ceramic load resistors onto the wires to make the current level match what the BMU was expecting. one of the issues with LEDs is they allow "unlimited" current through them untill they blow and this is what trips the BMU. adding load resistors will also reduce hyperflashing as the current in the LED switches on and off at a different threshold. what ill do if my K gets me home (intermitent engine cut out and start up Grrrr) is put my Meters on the K and do some sums for you the resistors normally cost a few $$ this my be an alternative to modding the BMU i will also pull my intergrated indicator/tail/brake light and plug it into my K for a testing at the weekend. as i say i have no experience fo the K BMU/Electrics but i cant imagine its to complex

if you can hang on a little im sure i can work a solution that doesnt require a mod the BMU

[Chri5]

i miss read you post a little there, the full brightness with out brakes applied is to much current you will need a resistor inline on the tail light wires most dual brightness LEDs just double up on current to switch between tail and brake (unless you can clealy see 2 set of leds) and a bypass resistor to con you BMU (if the K bike uses a reverse current to test the bulb)